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Background Renal transplant recipients have an increased cancer risk. The mammalian target of rapamycin inhibitor sirolimus (SRL) has immunosuppressive and antitumour activities but knowledge about its use in recipients with cancer is limited. Methods We retrospectively analysed 726 renal allograft recipients converted to SRL from 10 German transplant centres. Patient and graft survival were analysed depending on malignancy status prior to conversion and tumour entity. Results Malignancy before conversion to SRL was reported in 230 patients, with 137 patients having skin cancers and 101 having solid cancers. Cancer occurred 4.6 ± 9.4 (median 3.0) years after transplantation. Basal cell carcinoma, squamous cell carcinoma and Bowen's disease were the most prevalent skin cancers, while carcinomas of the kidney, colon and breast were the most prevalent solid cancers before conversion. Patients with prior malignancy were older and had better renal function at conversion compared with patients without a history of cancer. After conversion to SRL, cancer incidence rates (IRs) of all tumours were lower compared with rates before conversion. Cancer IRs after conversion were higher in patients with malignancy before conversion compared with those without. Patient survival was worse in patients with solid cancers compared with patients with skin cancers or without malignancies. Biopsy-proven acute rejections in the first year after conversion were less frequent in patients with malignancy compared with those without. Graft survival and renal function in all cancer types were better than in patients converted to SRL without cancers. Conclusions Conversion to SRL in patients with a history of cancer is safe regarding renal function and graft survival, while patient survival is largely dependent on tumour entity. [ABSTRACT FROM AUTHOR]

Background This prospective observational study documented long-term renal function in transplant recipients receiving mycophenolate mofetil ( MMF). Methods Kidney allograft recipients >6 months post-transplantation, with a glomerular filtration rate ( GFR) >20 mL/min, receiving MMF from time of transplantation were enrolled and followed for four yr. Subgroups were identified based on time between transplantation and enrollment: Y < 1 (6 months-1 yr); Y1-2 (>1-2 yr); Y2-5 (>2-5 yr) and Y > 5 (>5 yr). Results A total of 2040 patients were analyzed; 780, 410, 541 and 309 in subgroups Y < 1, Y1-2, Y2-5 and Y > 5. For all patients combined GFR decreased during the observational period by approximately 1 mL/min/yr (median GFR (mL/min) was 50.8, 50.5, 48.7, and 47.6 at one, two, three, and four yr). Survival estimates for decline in renal function (>20% GFR decline at one time point) were 78%, 66%, 57%, and 51% at one, two, three and four yr, with no significant differences between subgroups (p > 0.05). In adult patients, higher doses of MMF (≥1 g/d) were associated with better GFR outcomes (median GFR (mL/min) 48.1 vs. 39.9 at four yr post-enrollment; p = 0.0037). When comparing the effects of MMF combined with calcineurin inhibitors ( CNIs), GFR was increased with lower doses of tacrolimus or cyclosporin. There were no major tolerability or acute rejection problems and graft survival was similar in all subgroups (graft survival estimates for all patients combined were 99%, 95%, 92%, and 90% at one, two, three, and four yr). Conclusions Long-term MMF immunosuppression preserves renal function and higher MMF doses combined with lower CNI doses may provide better patient outcomes. [ABSTRACT FROM AUTHOR]

Oxygen tensions in the kidney are heterogeneous, and their changes presumably play an important role in renal physiologic and pathophysiologic processes. A family of hypoxia-inducible transcription factors (HIF) have been identified as mediators of transcriptional responses to hypoxia, which include the regulation of erythropoietin, metabolic adaptation, vascular tone, and neoangiogenesis. In vitro, the oxygen-regulated subunits HIF-1alpha and -2alpha are expressed in inverse relationship to oxygen tensions in every cell line investigated to date. The characteristics and functional significance of the HIF response in vivo are largely unknown. High-amplification immunohistochemical analyses were used to study the expression of HIF-1alpha and -2alpha in kidneys of rats exposed to systemic hypoxia bleeding anemia, functional anemia (0.1% carbon monoxide), renal ischemia, or cobaltous chloride (which is known to mimic hypoxia). These treatments led to marked nuclear accumulation of HIF-1alpha and -2alpha in different renal cell populations. HIF-1alpha was mainly induced in tubular cells, including proximal segments with exposure to anemia/carbon monoxide, in distal segments with cobaltous chloride treatment, and in connecting tubules and collecting ducts with all stimuli. Staining for HIF-1alpha colocalized with inducible expression of the target genes heme oxygenase-1 and glucose transporter-1. HIF-2alpha was not expressed in tubular cells but was expressed in endothelial cells of a small subset of glomeruli and in peritubular endothelial cells and fibroblasts. The kidney demonstrates a marked potential for upregulation of HIF, but accumulation of HIF-1alpha and HIF-2alpha is selective with respect to cell type, kidney zone, and experimental conditions, with the expression patterns partly matching known oxygen profiles. The expression of HIF-2alpha in peritubular fibroblasts suggests a role in erythropoietin regulation.